1. Technical Field
The disclosure relates to a reverse-bias preventing protection device, and more particularly to a motor controller with a reverse-bias preventing mechanism and a motor driving device.
2. Related Art
In the applications of motor driving, a motor controller is frequently connected to electric power in reverse polarity connection due to carelessness of assembly workers, and the reversed electric power may cause damage of the next level circuit components. For preventing the damages of the next level circuit components caused by the reverse connection of the electric power, a reverse-bias preventing unit is disposed between an input end of the electric power and the motor controller. The reverse-bias preventing unit is electric-conductive when the polarity of the electric power is connected in a positive bias, and is cut off when the electric power is connected in reverse bias, for preventing reversed electric power from damaging the motor controller and the next level circuit components.
Generally, the reverse-bias preventing unit is disposed on a main loop of a circuit structure. That is, the reverse-bias preventing unit is disposed on the main loop between the input end of the electric power and the motor controller, for preventing the next level circuit components and loads from being burned-out and damaged. In addition, the reverse-bias preventing unit is mainly implemented by a Schottky diode or a field effect transistor (such as a MOSFET).
Because the current of the electric power flowing through the main loop is relatively larger, thus the volumes of the Schottky diodes or the field effect transistors which are for implementing the reverse-bias preventing unit may be increased, which also increases the cost of the circuit. In addition, under the high-current working environment, the reverse-bias preventing unit with a larger volume may consume more power, thus the usage efficiency of electric power is relatively low, which also lowers the efficiency of power conversion of the motor controller. Therefore, the reverse-bias preventing mechanism of the motor controller needs to be improved.